The price of Britain's favourite foods face a steep hike if the Government pushes for a hard Brexit, former deputy prime minister Nick Clegg warns.
He said fears over the price of Marmite were just the tip of the iceberg - with the cost of chocolate, cheese and wine likely to be hit by a "triple whammy of punishing tariffs" if the UK leaves the EU's single market without a new trade agreement in place.
Ahead of a Lib Dem report on the impact of Brexit on the UK's food and drinks industry, he predicted that automatically reverting to the World Trade Organisation's trading rules will have serious consequences for consumers.
Mr Clegg, the party's European Union spokesman, said: "It's clear that Marmite was just the tip of the iceberg.
"A hard Brexit will lead us off a cliff edge towards higher food prices, with a triple whammy of punishing tariffs, customs checks and workforce shortages.
"The only way the Government will be able to avoid this outcome is if it maintains Britain's membership of the single market.
"We must hold Theresa May's Government to account and fight to ensure what comes next is best for British consumers and businesses."
The report, to be published later on Monday, says £11 billion worth of agricultural products the UK sells to the EU each year would be hit with an average tariff of 22.3%.
While tariffs on beef exports would be set at 59%, chocolate at 38%, cheese at 40% and wine at 14%.
Under WTO rules, tariffs will also apply to all imports into the UK until a trade deal with the EU is struck.
The higher tariffs could lead to a significant increase in food prices, compounded by increased costs to producers from extra red tape such as customs checks and labour shortages caused by the end of EU free movement.
The report also warns of a short-term hit to food prices in the coming months, as supermarket supplier contracts expire and have to be renewed at current exchange rates, which could force some companies out of business.